A drivetrain system on some machines, such as a wheel loader, may include a torque converter and a multispeed transmission as part of a mechanical drivetrain package. In some applications for machines, however, an electric drivetrain system may be desirable. Existing electric drivetrain systems typically require a multispeed drivetrain in order to meet run out speeds comparable to a performance provided by a mechanical drivetrain. Moreover, replacing mechanical drivetrain systems with electric drivetrain systems may require significant modification to the machine in order to meet the same performance. In this regard, electric drivetrain systems typically require electrical components which do not fit within a comparable space as mechanical drivetrain system components. This limits the adaptability of machines to implement an electric drivetrain system in lieu of a mechanical drivetrain system.
An electric drivetrain system replacing a mechanical drivetrain system includes an engine, a generator, a multispeed transmission, and a gear reduction. The multispeed transmission in combination with an electric motor and/or generator results in an electrical space claim that is larger than the mechanical drivetrain space claim associated with the mechanical drivetrain system. This is at least in part because the multispeed transmission and the electric motor are added to the drivetrain of the electrical system. Accordingly, replacing a mechanical drivetrain system with an electric drivetrain system requires significant architectural modification of the machine due to the substantially increased space claim of the electrical drivetrain system.
U.S. Pat. No. 7,957,855, titled “Control system for hybrid vehicle,” discloses a hybrid vehicle with a generator coupled to a single electric motor through a switch to supply current from a generator to a motor to drive a vehicle. However, this patent does not provide a configuration for an electric drivetrain system to fit substantially within the same space as a comparably performing mechanical drivetrain system.
Accordingly, an electric drivetrain system which can replace a mechanical drivetrain system while substantially fitting within the same space, and which can meet the performance of the mechanical drivetrain system is needed.